July in Siem Reap is the windiest month of the year. In July, the weather in Siem Reap is typically hot. Average daily high temperature in July is about 30 degrees above zero. On average, Siem Reap has 31 rainy days in July. The rains are usually heavy. July as well as April, May, June, and August is considered the most uncomfortable time to visit Siem Reap.